Apparatus for classifying dry solids



May 23, 1967 w. .1. SACKETT, SR 3,321,079 I APPARATUS FOR CLASSIFYING DRY SOLIDS Original Filed Aug. 27, 1963 5 Sheets-Sheet 1 INVENTOR Walter J. Sac/rah, 5r.

, ATTORNEY May 23, 1967 w. J. SACKETT, SR

' APPARATUS FOR CLASSIFYING DRY SOLIDS 5 Sheets-Sheet 2 Original Filed Aug. 27, 1963 INVENTOR Wa/ler J. Sac/ref), 5r:

BY Mal/ L11 Ji /u May 23, 1967 w. J. SACKETT, SR

APPARATUS FOR CLASSIFYING DRY SOLIDS 5 Sheets-Sheet 5 Original Filed Aug. 27, 1963 Wa/fer J. Sac/rah, $1:

I BY

y 1967 w. J. SACKETT, sR 3,321,079

APPARATUS FOR CLASSIFYING DRY SOLIDS Original Filed Aug. 27, 1963 5 Sheets-Sheet 4 ATTORNEY May 23, 1967 w. J. SACKETT, SR 3,321,079

APPARATUS FOR CLASSIFYING DRY SOLIDS Original Filed Aug. 27, 1963 5 Sheets-Sheet 5 INVENTOR Waller J. Sac/(eff, Sr.

ATTORNEY United States Patent 3,321,079 APPARATUS FOR CLASSIFYING DRY SOLIDS Walter J. Sackett, Sr., 3700 Echodale Ave., Baltimore, Md. 21206 Continuation of application Ser. No. 304,805, Aug. 27, 1963. This application June 21, 1966, Ser. No. 563,013 2 Claims. (Cl. 209-38) This application is a. continuation of US. patent application Ser. No. 304,805, now abandoned, filed by applicant on Aug. 27, 1963, for Method and Apparatus for Classifying Dry Solids."

This invention relates generally to classifying apparatus, and more particularly it pertains to improvements in mesh-type sifters for classifying dry solids.

It is required in many industrial processes to restrict a product to a close range of particle size, neither too fine nor too coarse. This is usually done in two stages of sifting, one stage passing all sizes above a given maximum and one stage passing all below a given minimum particle size. The material retained in the second stage then is the desired product of size intermediate to the two extremes.

If care is not taken, the sifting screens become clogged and no longer function correctly causing considerable waste and variation in the product quality.

It is an object of this invention, therefore, to provide a continuous process apparatus for classifying which is particularly effective for dry solids such as chemical fertilizer, feeds, seeds, and the like and which is self-cleaning and regulating.

Another object of this invention is to provide a compact, efficient sifter with brush cleared mesh panels which can be easily and quickly changed.

To provide a granular product classifier which operates at a controlled, constant, continuous rate either horizontally or inclined, is yet another object of this invention.

Other objects and attendant advantages of this invention will become more readily apparent and understood from the following detailed specification and accompanying drawings in which:

FIG. 1 is a side elevation of a classifying apparatus for dry solids which incorporates features of this invention;

FIG. 2 is a vertical section view of the apparatus of FIG. 1;

FIG. 3 is a section taken on line 33 of FIG. 1;

FIG. 4 is a perspective view of a screen panel;

FIG. 5 is a detail, much enlarged, showing the bar attachment means for the chains;

FIG. 6 depicts the same detail as in FIG. 5 viewed in a different direction;

FIG. 7 is a vertical section similar to FIG. 2 of an inclined arrangement of the apparatus providing increased screen area without loss of efiiciency from gravitational effect; and

FIG. 8 is a vertical section of the preferred embodiment of the invention illustrating still further improvements in compactness and efficiency.

Referring now to the details of the drawings and particularly FIGS. 1 and 2, the improved classifier consists of two hoppers 10 and 12 mounted one above the other in a framework 14.

Both hoppers 10 and 12 are totally enclosed and provided with covers 16 and 18, respectively. Each cover 16 and 18 is provided with an inlet port and exit port 20 and 22, respectively, both the full width of each cover located at opposite ends thereof.

A supply hopper 24 (shown in part) is connected to the inlet port 20 of cover 16 to introduce raw granular or pelleted material thereto for conveyance to the right across a screen panel 26.

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This screen panel 26 lies horizontally across the mouth of the intermediate hopper 10. Any material entering from the hopper 24 must thus pass through panel 26.

Hopper 10 collects this material and introduces it to the inlet port 20 of the lower cover 18 for conveyance to the right across a similar screen panel 28 lying horizontally across the mouth of the fines hopper 12. Any material entering the hopper 12 must pass through or across screen panel 28.

The mesh 30 of the upper screen panel 26 is made coarse weave while that for the lower screen panel 28 is made relatively finer weave.

Material rejected by mesh 30 is passed to the respective outlet ports 22 of each cover 16 and 18 and is discharged as oversize material into chute 32 or sized product in chute 34. The rejected fines are collected in hopper 12 and channeled off by fines chute 35.

A mechanism 36 for conveying the material across the panels 26 and 28 and for cleaning the mesh 30 thereof is located in the covers 16 and 18. This mechanism 36 consists of a pair of sprockets 38 spaced and secured upon shafts 40 as best shown in FIG. 3. Each shaft 40 is mounted for rotation in a horizontally adjustable journal 42 (see FIGS. 1 and 2) on the outside of each cover. The journal 42 is also spring-loaded downwardly by a coil compression spring 44 and backed up with an adjust ing screw 46 beneath. A drive pulley 48 is mounted on an extension 50 of one shaft 40 of each mechanism. This drive pulley 48 is belted to a drive motor 52.

The sprockets 38 are provided with endless chains 54 which extend inside the covers from the inlet to outlet end. As best shown in FIGS. 3 and 5, a plurality of spaced traveling bars 56 each extending across from one chain 54 to its opposite counterpart of chain 54 are secured by brackets 58 thereto so as to be carried around in succession and pass over the mesh 30 of the screen panels in the direction of the arrows in FIG. 2.

Some of these traveling bars 56 carry a bristle brush 60 as shown in FIG. 6 while others carry a magnetized face 62 as shown in FIG. 3 to extract tramp iron. The bristle brush 60 is sufficiently long to bear against the mesh 30. The magnetized face is arranged to just clear the mesh. As shown in FIG. 4 it is preferable to use a weave for mesh 30 which provides rectangular openings. The panel 26 (28) is then installed through the access door 64 from the side so the travel of brush 60 is parallel to the length of the mesh openings.

As shown in FIG. 7 an inclined attitude in given to the hopper covers, reference numerals 66 and 68, in this second embodiment of the invention. The conveyor mechanism 36 functions efiiciently in this. arrangement. The traveling bars 56 meter the introduction of material to the meshes 30 from the supply chute 24 or intermediate hopper 10 to prevent overloading. Clogging of material is virtually impossible as the brushes 60 at the tips of the bars 56 enter the openings in the mesh .30 and sweep across the panels 26 and 28. The greater area of mesh 30 is apparent with no increase in floor space occupied by the framework 14.

In FIG. 8 a preferred and more compact arrangement in an inverted inclined direction is shown. Still further an important change has been made in the placement of the supply hopper 24 for the wiper screen and the port for hopper 10 for the lower screen, both now being located at the lower ends of their respective inclined conveyer mechanisms 36. Accordingly, the direction of movement of these mechanisms 36 has been reversed so as to convey the fed material in an upwardly direction over the screen panels 26 and 28 (see directional arrows).

Comparison is invited between FIGS. 7 and 8 to emphasize the much more eflicient utilization of space in the 3 latter arrangement to achieve the same result. Moreover, with the discharge chutes 32 and 34 at the. upper ends of the covers 66 and 68, there is full assurance that material discharged therefrom has been conveyed over the screens and not arrived by gravity alone perhaps bypassing the screens enroute.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. Apparatus for classifying particulate material, comprising structure defining a frame, a first screen panel mounted within said frame for receiving said particulate material, a second screen panel of smaller mesh than said first screen panel mounted within said frame beneath first screen panel, a hopper receiving the undersize of said particulate material from said first screen panel and directing said undersize to one end of the upper surface of said second screen panel, a pair of rotatably mounted sprockets mounted above each end of each said screen panel and adjacent to the longitudinal sides thereof, roller chains operatively connected with pairs of longitudinally aligned sprockets, spaced bars positioned across the upper surface of each said screen panel and secured to their respective roller chains, means rotating said sprockets whereby said spaced bars traverse the upper surface of each said screen panel, each said screen panel having rectangular mesh, with the long dimension of said mesh extending in the direction of traversal of said spaced bars, bristle brushes mounted on some of said spaced bars and having the tips of said brushes arranged to bear against said mesh of its respective panel for clearing each said screen panel of particulate material and for conveying oversize particulate material from one end to the opposite end of each said screen panel, magnetized faces mounted on the remaining of said spaced bars and spaced above said panels for extracting magnetic material from the mesh of each said screen panel, and means for receiving the oversize of said particulate material from said second screen panel.

2. The apparatus as recited in claim 1 wherein said sprockets are biased towards their respective screen panel.

References Cited by the Examiner UNITED STATES PATENTS 186,041 1/1877 Montagu 209-389 X 417,836 12/1881 Ponsar 209-390 X 499,994 6/ 1893 Higginson 209-358 573,706 12/1896 Rossiter 209358 X 751,150 2/1904 Dear 209218 889,811 6/1908 Ruddick 209--316 X 1,432,921 10/1922 Swanson 20937 X 2,053,038 9/1936 Mackenzie 209358 X HARRY B. THORNTON, Primary Examiner.

R. HALPER, Assistant Examiner. 

1. APPARATUS FOR CLASSIFYING PARTICULATE MATERIAL, COMPRISING STRUCTURE DEFINING A FRAME, A FIRST SCREEN PANEL MOUNTED WITHIN SAID FRAME FOR RECEIVING SAID PARTICULATE MATERIAL, A SECOND SCREEN PANEL OF SMALLER MESH THAN SAID FIRST SCREEN PANEL MOUNTED WITHIN SAID FRAME BENEATH FIRST SCREEN PANEL, A HOPPER RECEIVING THE UNDERSIZE OF SAID PARTICULATE MATERIAL FROM SAID FIRST SCREEN PANEL AND DIRECTING SAID UNDERSIZE TO ONE END OF THE UPPER SURFACE OF SAID SECOND SCREEN PANEL, A PAIR OF ROTATABLY MOUNTED SPROCKETS MOUNTED ABOVE EACH END OF EACH SAID SCREEN PANEL AND ADJACENT TO THE LONGITUDINAL SIDES THEREOF, ROLLER CHAINS OPERATIVELY CONNECTED WITH PAIRS OF LONGITUDINALLY ALIGNED SPROCKETS, SPACED BARS POSITIONED ACROSS THE UPPER SURFACE OF EACH SAID SCREEN PANEL AND SECURED TO THEIR RESPECTIVE ROLLER CHAINS, MEANS ROTATING SAID SPROCKETS WHEREBY SAID SPACED BARS TRAVERSE THE UPPER SURFACE OF EACH SAID SCREEN PANEL, EACH SAID SCREEN PANEL HAVING RECTANGULAR MESH, WITH THE LONG DIMENSION OF SAID MESH EXTENDING IN THE DIRECTION OF TRAVERSAL OF SAID SPACED BARS, 